A beam trap for absorbing radiant energy of undesired laser radiation is disclosed in DE 10 2010 036 161 A1. The beam trap described there includes two reflectors, where at least one of the two reflectors is provided with a coating that absorbs radiant energy. The two reflectors are positioned relative to one another such that the laser radiation, which is incident on a first reflector and is then reflected, is directed onto the second reflector. The laser radiation, which is incident on the second reflector and then reflected, is directed back onto the first reflector, with the result that the radiant energy of the laser radiation is absorbed after multiple reflections and the resulting continuous partial absorption.
EP 1 950 000 A1 describes an apparatus having a beam generator for generating a beam, and having a beam trap device. The beam trap device has aluminum plates having planar surfaces which are located opposite one another. The beam is directed onto the beam trap device and destroyed in the beam trap device as a result of repeated reflection from the first to the second surface and from the second to the first surface.
Back reflections coming from beam traps have a disturbing effect on the functionality of optical arrangements in which the beam traps are used. For this reason, it is advantageous if a beam trap absorbs the radiant energy of an incident beam to the greatest possible degree. The problem arises in conventional beam traps, in particular in the case in which the power of the incident beam is very high, for example more than approximately 50 kW, that the radiant energy may not be able to be absorbed completely. In addition, degradation phenomena of the materials used in the beam trap may occur when using beam traps for absorbing (pulsed) high-power laser beams.